Look at it this way. If u play 12 nrg normally (lets say 8 fire 4 call) and 2 fire get prized. That means u have 6 nrg to use to draw with Ninetales AND attack with whoever. FOR THE WHOLE GAME. And if u run such a low count chances are you won't have them when u need them to draw/attack. I don't know of a deck that can run on 6 energy consistently...Raybees doesn't count shhhhh
Lets say u run 15 with 2 Call tho, and 3 fire get prized. You still have 12 nrg to draw with, and you'll probably discard 4-6 in the course of the game with Ninetales. That still gives you 6 fires for attacking, plus the prized ones and the Calls.
So I guess the rule of thumb is to play 6 fire for 9tales, then your normal nrg count. If u can't fit 6 more fire into your deck you should probably just go with Claydol.
I will say that Infernape Lv. X (DP) is probably the best partner for 9tales, or at least has more synergy with Ninetales than anything out right now.